Single-agent Trastuzumab in patients with pretreated HER-2 positive metastatic breast cancer: Response, survival and tolerability

The following is an abstract taken from the 27th ESMO Conference.

Purpose

To evaluate the efficacy and safety of single-agent Trastuzumab in women with HER2-positive metastatic breast cancer after failure of one of more chemotherapy regimens for metastatic disease.

Patients and methods

70 patients (pts) aged 28 to 74 (mean 54.4 +/- 11.1) years were recruited from 28 institutions in Germany. 67 patients are available for analysis.

HER2 status was DAKO HercepTest 3+ in 96% and 2+/FISH+ in 4%. The median number of chemotherapy regimens was 3: 88% had received prior anthracyclines and 64% taxanes; 60% had received hormonal therapy. Median number of metastatic sites was 2: 52% had liver, 27% lung, 48% bone and 3% CNS metastases. Performance at study entry ranged from 70 to 100%, with a median of 90%. 2 pts had evidence of cardiac disease by electro- and echocardiography at baseline but qualified for enrolment. Trastuzumab was administered at an initial dose of 4mg/kg followed by weekly doses of 2mg/kg thereafter until disease progression.

Results

62 pts are evaluated for efficacy. Trastuzumab treatment duration ranged from 1 to 66 weeks (median: 12), with 3 pts still on therapy. Objective responses (CR/PR) were seen in 12/62 pts (19%; 3 CR), while another 11% showed stabilization of disease for >6 months. Duration of response was 44 weeks. TTP was 12 weeks, with 10% of pts having progression-free survival >1 year. Side effects related to Trastuzumab, evaluable in 66 patients, were generally mild. Flu-like symptoms were the most common event (44%). Significant cardiac problems were detected in 3 cases, all with anthracycline pretreatment, and Trastuzumab was withdrawn on 2 pts. Survival data will be reported.

Conclusion

Pts with HER2-positive metastatic breast cancer obtain benefit from Trastuzumab monotherapy even after heavy pretreatment. The efficacy and tolerability profile are similar to those in another trials of Trastuzumab monotherapy.